Studies have shown that the uniformity of ammonia distribution in the exhaust gas after-treatment system (such as Selective Catalytic Reduction system, SCR system) has a significant impact on the overall performance and durability of the system. If the ammonia distribution is not uniform, it will cause too much ammonia in the local area and easily cause ammonia leakage, while in other ammonia-thin areas, the conversion efficiency of nitrogen oxides (NOx) will be too low. The uneven distribution of ammonia over a long period of time will lead to uneven aging of the catalyst, which will affect the overall performance of the catalyst. In addition, the uneven distribution of urea droplets will cause the temperature of the local pipe wall or the mixed structure to be too low, forming crystals, and in severe cases, the exhaust pipe will be blocked, resulting in a decrease in engine power performance.
Therefore, it is necessary to provide a new type of exhaust gas after-treatment mixing device and an exhaust gas after-treatment package therefor to solve the above technical problems.